Radial- oder diagonalventilator

ABSTRACT

The invention relates to a radial fan with an impeller ( 100 ) and a cylindrical drive unit ( 200 ) that can be rotated around the longitudinal axis, whereby the impeller ( 100 ) consists of a baseplate and of blades ( 101 ) arranged on the baseplate, and whereby the blades are located on the side facing the main air flow, and it is characterized in that the impeller ( 100 ) can be operatively connected to the drive unit ( 200 ) in two fastening planes. The impeller consists of a baseplate and blades arranged on the baseplate, whereby the blades are located on the side of the baseplate facing the main air flow, and whereby the baseplate is made up of an upper shell located on the side facing the main air flow and of a lower shell located on the side facing away from the main air flow, whereby the upper shell and the lower shell form a closed cavity with the cylindrical drive unit when in the installed state, whereby a first fastening plane is located on the upper shell and a second fastening plane is located on the lower shell.

The invention relates to a radial or diagonal fan with an impeller and a prismatic drive unit that can be rotated around the longitudinal axis, whereby the impeller consists of a baseplate and of blades arranged on the baseplate, and of a cover plate as a closure, and whereby the blades are located on the side facing the main air flow.

Nowadays, radial fans with blades that are curved backwards or diagonal fans are used on a widespread scale. The area of application ranges from their use in household appliances such as, for example, exhaust hoods, in air-conditioning units and even in a wide array of industrial systems. With a radial or diagonal fan, the air is drawn in parallel or axially relative to the drive axis of the radial or diagonal fan and is then blown out radially or diagonally by the rotation of the radial impeller.

Fundamentally, radial or diagonal fans consist of a drive unit and an impeller. The drive unit of a radial or diagonal fan can be configured, for instance, as an asynchronous motor or of a permanent-magnet synchronous motor (electronically commutated EC motor). The radial impeller or diagonal impeller is connected to the rotor of the drive unit and serves to convey air and/or other gases. The material selection of today's impellers ranges from plastic versions to metal structures. Nowadays, for strength-related reasons, impellers with fairly large diameters (typically 630 mm and larger) are in the form of a simple sheet metal construction. For strength-related reasons, aluminum or sheet steel that is relatively thick (typically 5 mm and more) is used. In the state of the art, impellers with a diameter of 800 mm are known whose cover plate has a thickness of 4 mm, a blade thickness of 6 mm and a baseplate thickness of 5 mm. Owing to the relatively large amount of material employed, this yields impellers that have a high intrinsic weight and that are thus correspondingly expensive to produce. Another consequence of the high weight is that the drive unit and the other components are subject to a high load. In order to reliably absorb this load and to reliably support the high intrinsic weight, the drive unit and the other components have to be solid, which likewise translates into high costs.

The objective of the invention is to reduce the above-mentioned drawbacks.

According to the invention, this objective is achieved by a radial or diagonal fan according to claim 1. Advantageous embodiments can be gleaned from the subordinate claims 2 to 20.

A radial or diagonal fan according to the invention has an impeller and a prismatic drive unit that can be rotated around the longitudinal axis, whereby the impeller can be operatively connected to the drive unit in two fastening planes. Thanks to the fastening in two planes, the flexural strength is increased, thereby achieving a greater system strength of the radial or diagonal fan without increasing the weight.

The impeller has a baseplate and blades arranged on the baseplate as well as, optionally, a cover plate as a closure, whereby the blades are located on the side of the baseplate facing the main air flow, and whereby the baseplate is made up of an upper shell located on the side facing the main air flow and a lower shell located on the side facing away from the main air flow, whereby the upper shell and the lower shell form a closed cavity with the cylindrical drive unit when in the installed state, whereby a first fastening plane is located on the upper shell and a second fastening plane is located on the lower shell. The wall thickness of the material employed can be reduced by the shell construction, as a result of which the weight of the radial or diagonal fan is reduced even further. Thanks to the fastening in the two planes, the stiffness of the radial or diagonal fan is nevertheless retained.

Advantageously, on the edge of the upper shell and of the lower shell facing the drive unit, there are fastening means that create a detachable connection together with fastening means on the cylindrical drive unit when in the installed state. Consequently, the impeller can be installed on or removed from the drive unit.

Advantageously, the upper shell and the lower shell are connected by screwed connections to flanges that are arranged on the cylindrical drive unit so as to be offset in the longitudinal axis. Since the flanges are offset, they can connect the upper shell and the lower shell to the drive unit in such an offset manner that a particularly stable connection is created between the drive unit and the impeller.

Advantageously, the fastening means in the upper shell, relative to the longitudinal axis of the rotatable cylindrical drive unit, are arranged radially offset to the fastening means of the lower shell. The radially offset arrangement allows a simpler installation of the impeller on the flanges of the drive unit.

Advantageously, there are installation holes in the upper shell or in the lower shell opposite from the fastening means, which are concealed when in the installed state. Thus, it is possible to access the fastening means without removing the impeller from the drive unit.

In an especially advantageous embodiment, the installation holes have a larger diameter than the holes in the lower shell and in the upper shell. As a result, a tool, for example, a socket wrench, can be inserted through the installation hole. For the installation, it has proven to be especially advantageous to use fastening means in the form of nuts that are screwed onto threaded bolts. In particular, staked nuts can be used that have an outer diameter widening, for example, in the form of a permanently attached washer. These staked nuts can be picked up, for instance, with the magnetizable socket of a socket wrench and installed. As a result, the nut can be screwed onto a threaded bolt that is concealed and that ends in the cavity, without the possibility that the nut might be lost during the installation. As a result, a reliable installation and, in particular, a reliable automatic installation, is possible. A nut that is lost during the installation severely disrupts the installation process. If the nut is lost in the cavity, it has to be retrieved from there with a great deal of effort. It would not be possible to use the radial fan with a loose nut in the cavity.

Advantageously, the fastening means in the upper shell and the fastening means in the lower shell have holes or threaded bolts that are operatively connected to holes or threaded bolts of the flanges when in the installed state. This allows a simple installation of the impeller on the drive unit via the threaded bolts that can be inserted into the holes. Subsequently, the threaded bolts can be screwed with fitting nuts.

Advantageously, the upper shell and/or the lower shell have centering means that cooperate with centering means on the flanges that have been put in place. The centering means simplify the correct installation of the impeller on the drive unit. Advantageously, the centering means are centering projections and centering indentations that cooperate during the installation of the impeller on the cylindrical drive unit.

Advantageously, the upper shell is configured to be rotation-symmetrically curved in such a way that it curves in the direction of the main air flow. As a result, flow separations are avoided. At the same time, this shape enhances the efficiency.

Advantageously, the upper shell has several sections that have at least one concave section or one convex section or one flat section.

Advantageously, the lower shell is configured to be flat, which leads to a reduction of the costs for tools and parts.

Advantageously, the cavity has at least one reinforcement that runs as a round or polygonal ring axially around the cylindrical drive unit. This reinforcement makes it possible to use thin materials, even under high loads.

Advantageously, the cavity has at least one reinforcement that extends radially relative to the longitudinal axis of the rotatable cylindrical drive unit. This ensures a flux of force from the flanges to the blades.

Advantageously, the blades arranged on the baseplate are configured with a shell design. This further reduces the weight of the impeller.

Advantageously, the contours of the blades arranged on the baseplate are configured to be smooth on the side facing the main air flow, as a result of which better efficiency can be achieved and flow-related disturbances can be reduced.

In another advantageous embodiment, the flanges of the drive unit extend to differing extents radially relative to the longitudinal axis. This simplifies the installation of the radial fan in the axial direction.

Moreover, it has proven to be advantageous for installation holes to be arranged in the flanges opposite from the fastening means, which are concealed when in the installed state.

In addition, it is advantageous for the installation holes to have a larger diameter than the holes in the lower flange and in the upper flange. The advantages of this are analogous to those indicated above for the diameter of the installation holes of the upper shell and lower shell.

The drive unit of the radial fan can be a rotor or a shaft connection.

The structural design of the fastening in conjunction with the lightweight construction of the impeller allows a higher motor utilization and has positive effects in terms of the service life of the motor.

Additional advantages, special features and practical refinements of the invention can be gleaned from the subordinate claims and from the presentation below of preferred embodiments making reference to the drawings.

The drawings show the following:

FIG. 1 an exploded view of a radial fan with a section through the impeller in a first embodiment,

FIG. 2 a three-dimensional view of the radial fan in the installed state according to FIG. 1,

FIG. 3 a section through a radial fan according to another embodiment,

FIGS. 4 a-f schematic views of the connection of the impeller to the drive unit according to another embodiment,

FIGS. 5 a-e sectional views through a radial fan according to another embodiment,

FIG. 6 two three-dimensional views of drive units according to other embodiments.

In the various figures of the drawing, the same parts are always designated with the same reference numerals and consequently, as a rule, are only described once.

As FIGS. 1 and 2 illustrate, a radial fan according to the invention consists of an impeller 100 and a cylindrical drive unit 200. The impeller 100 is connected to the drive unit 200 by means of fastening means that will still be explained in greater detail below. Here, FIG. 1 shows an exploded drawing of the radial fan and FIG. 2 shows the radial fan in the assembled or installed state. The radial fan serves to convey a gas or a liquid by means of blades 101 that are located on the impeller and that are arranged on a baseplate of the impeller 100. The impeller 100 rotates with the cylindrical drive unit 200 around a longitudinal axis that runs through the center in the lengthwise direction of the drive unit 200.

According to the invention, the baseplate consists of an upper shell 102 and a lower shell 103, whereby the upper shell 102 faces the main air flow and conveys the gas or liquid with the blades 101. The gas or the liquid is drawn in parallel or axially relative to the drive axis of the radial fan, and is then blown out radially or diagonally by the rotation of the radial impeller. For the sake of clarity, only the application case involving transporting air will be mentioned below, whereby the transport of other gases can always be meant here as well. The main air flow could thus also be a main flow of any gas. Thus, the term “main air flow” also includes the main gas flow. The space of the main air flow is defined by the blades 101 in conjunction with the upper shell 102 of the baseplate and with the wall (e.g. the rotor 201) of the drive unit 200, since the main portion of the transported medium is moved here. The upper shell 102, together with the lower shell 103, forms a cavity 104 that, in the installed state, is closed off with the rotor 201. The upper shell 102 and the lower shell 103 are arranged rotation-symmetrically around the drive unit 200, which can be rotated around the longitudinal axis. The two shells can be joined by riveted connections, screwed connections, welded connections, stamped connections, pressed connections, or adhesive connections. It is also possible to combine the impeller with a baseplate or cover plate that is not rotation-symmetrical.

In order to increase the stability of the baseplate, reinforcement ribs 105, 106 can be arranged in the cavity 104 between the upper shell 102 and the lower shell 103, and these reinforcement ribs 105, 106 can further subdivide the cavity 104. The reinforcement 105 can be configured in the form of at least one ring that is arranged axially around the longitudinal axis and that is configured to be either round or polygonal. This ensures a uniform distribution of the weight on the rotating baseplate. The reinforcement 106, however, can also run radially relative to the longitudinal axis, as is shown in FIG. 3. This arrangement of the reinforcement 106 ensures a flux of force from the drive unit 200 all the way to the blades 101.

Preferably, the blades 101 have a hollow profile, that is to say, they are designed to be hollow. This distributes the introduction of force into the baseplate and the cover plate, thereby leading to reduced peak stresses and thus reducing the metal plate thicknesses as well as the weight of the impeller 100. Moreover, the side of the blades 101 facing the main air flow is preferably configured to be smooth in order to avoid swirling.

The cylindrical drive unit 200 can be a rotor 201 of an asynchronous motor or of a permanent-magnet synchronous motor as is shown in FIGS. 1 to 6. However, it is also possible for the drive unit 200 to be a shaft that is driven by a motor.

Around the rotor 201, there are two ring-shaped flanges 202, 203 that project radially outwards and that have fastening means to fasten the impeller to the rotor 201 of the drive unit 200. The flanges 202, 203 are arranged in two planes that are offset axially relative to the longitudinal axis, whereby the distance between the flanges is approximately the same as the distance between the upper shell 102 and the lower shell 103 on the side facing the rotor 201. Therefore, in the installed state, the upper shell 102 is connected to the flange 202 that is closest in the main air flow, and the lower shell 103 is connected to the second flange 203. Thus, the baseplate of the impeller 100 is connected via two ring-shaped fastening means to the rotor 201 of the cylindrical drive unit 200, as is shown in a sectional view in FIG. 3.

FIG. 3 shows a section through the impeller 100 and through parts of the rotor 201. The impeller 100 has a largely flat lower shell 103 as well as a curved upper shell 102, which together form a cavity 104. According to this embodiment, a reinforcement rib 106 is arranged in the cavity 104 radially relative to the longitudinal axis of the drive unit 200. Two flanges 202, 203 are arranged on the rotor 201 of the drive unit 200, whereby the one flange 202 is connected to the upper shell 102 while the other flange 203 is connected to the lower shell 103 by fastening means.

FIGS. 4 a-f show various embodiments of upper shells 401 a-d and lower shells 402 a-d that can be connected to various flanges 403 a-d, 404 a-d. The upper shells 401 a-d and the lower shells 402 a-d have different diameters and different fastening means. The individual embodiments will be described below. FIG. 4 a shows an upper shell 401 a that has a larger diameter than that of the lower shell 402 a. This means that, during the installation onto the rotor 201, the upper shell 401 a is closer to the rotor 201 than the lower shell 402 a is. The flanges 403 a, 404 a have to be configured in such a way that, during the installation of the impeller 100 onto the rotor 201, the lower shell 402 a can slide past the flange 403 a for the upper shell 401 a axially relative to the longitudinal axis of the drive unit 200. In the embodiment of FIG. 4 a, the impeller is installed from above, that is to say, axially from the direction of the main air flow, so that the lower shell 402 a can slide past the flange 403 a for the upper shell 401 a. Consequently, the flange 403 a for the upper shell 401 projects radially to a lesser extent from the rotor than the flange 404 a for the lower shell 402 a does. This geometric arrangement of the upper and lower shells as well as of the flanges is also present in the embodiments of FIGS. 4 c and 4 e. In the embodiments of FIGS. 4 b, 4 d and 4 f, the geometry of the shells and flanges is reversed, so that the impeller 100 has to be installed from below (the side facing away from the main air flow). The upper shell 401 a and the lower shell 402 a are provided with threaded bolts 407, 408 that are accommodated in corresponding holes 406 a, 409 a. Thus the holes 406 a, 409 a and the threaded bolts 407, 408 are fastening means for fastening the impeller 100 onto the rotor 201. For the sake of clarity, additionally needed nuts or locknuts are not shown in FIGS. 4 a-f. The flange 404 a in FIG. 4 a additionally has an installation hole 405 a that makes it possible to access the threaded bolt 408 of the upper shell 401 a for installation purposes. FIG. 4 b shows a reversed arrangement, so that the upper shell 401 b can be installed with its threaded bolt 408 in the hole 409 b of the upper flange 403 b. The lower shell 402 b is installed via the threaded bolt 407 onto the lower flange 404 b via the hole 406 b, whereby there is an installation hole 405 b in the upper flange. FIGS. 4 c and 4 d show two embodiments by way of example in which the threaded bolts 410, 411 are arranged on the flanges 403 c, 403 d, 404 c, 404 d, which can engage into the holes 409 c, 409 d of the upper shell 401 c, 401 d and into the holes 406 c, 406 d of the lower shell 402 c, 402 d. No nuts are shown here either. In FIG. 4 c, the upper shell has an installation hole 405 c. In FIG. 4 d, the installation hole 405 d has been made in the lower shell 402 d.

Instead of the permanently attached threaded bolts 407, 408, it is also possible to use open threaded bolts or threaded rods 412, which are shown accordingly in FIGS. 4 e and 4 f. In FIG. 4 e, installation holes 405 c, 405 a are arranged in the upper shell 401 c and in the lower flange 404 a. The embodiment according to FIG. 4 f has the corresponding installation holes 405 b, 405 d in the upper flange 403 b and in the lower shell 402 d. For all of the embodiments of FIGS. 4 a-f, it applies that multiple fastening means can be attached around the rotor 201.

The embodiments of FIGS. 5 a-e show different configurations of the upper shell 102 in sectional views. Thanks to these different embodiments, depending on the medium, flow-related losses can be diminished and the noise emissions can be reduced. FIG. 5 a shows an upper shell 102 that is divided into several sections, whereby the sections are configured to be concave, convex or rectilinear or else conical. FIG. 5 b shows a curvature of the upper shell 102 in the direction of the lower shell 103. As shown in FIG. 5 c, the upper shell 102 can be curved in the direction of the main air flow. FIG. 5 d shows a rectilinear configuration of the upper shell 102. FIG. 5 e summarizes these different configurations once more. Due to the shape of the upper shell, which can be altogether described as pot-like, the efficiency and the sound level that is created can be improved by 0.5% to 5%. When thin sheet metal (approximately 0.5 mm to 2 mm) is used, the division of the baseplate into an upper shell 102 and a lower shell 103 can lead to a drastic weight reduction by more than 50%. The lower weight of the impeller according to the invention results in high eigenfrequencies and high critical rotational speeds. The lower shell 103 is preferably configured to be flat.

FIG. 6 shows two embodiments of rotors. The rotor 601 has no cooling ribs, whereas the rotor 201 has cooling ribs. If the cooling elements or cooling ribs are situated in the main air flow, swirling can occur. In contrast, cooling elements are needed in order to cool the motor. This cooling is particularly important in the area around which air flows. In the embodiment of the rotor 601 without cooling ribs, FIG. 6 also shows that, on the flanges 602, 603, there can be centering projections 605 or centering holes 606 that cooperate with corresponding centering projections and the centering holes in the upper shell and in the lower shell, thereby simplifying the installation of the impeller. Owing to the centering projections 605 and centering holes 606, the basic unbalance of the impeller 100 can be improved, thereby resulting in a reduction in the number of balancing cycles during the production of the impeller 100. Since a flange 603 projects further radially outwards, a stiffening step 607 can be attached to this flange 603 in order to increase the stability, so that the flange is cranked. Moreover, FIG. 6 shows threaded bolts 604 that are configured as press-in threaded bolts 604. The press-in threaded bolts 604 can also have additional centering projections, thereby facilitating the installation. With the press-in threaded bolts 604, one can also use locknuts instead of simple nuts. This allows a better hold and centering by means of a socket wrench. In this way, the nuts or screws can be largely prevented from being tilted or lost.

LIST OF REFERENCE NUMERALS

-   100 impeller -   101 blade -   102, 401 a-d upper shell -   103, 402 a-d lower shell -   104 cavity -   105, 106 reinforcement rib -   200 drive unit -   201, 601 rotor -   202, 403 a-d, 602 upper flange -   203, 404 a-d, 603 lower flange -   405 a-d installation hole -   406 a-b hole in the lower flange -   406 c-d hole in the lower shell -   407 threaded bolt on the lower shell -   408 threaded bolt on the upper shell -   409 a-b hole in the upper flange -   409 c-d hole in the upper shell -   410 threaded bolt on the lower flange -   411 threaded bolt on the upper flange -   412 open threaded bolt -   604 press-in threaded bolt -   605 centering projection -   606 centering hole -   607 stiffening step 

1. A radial or diagonal fan with an impeller and a prismatic drive unit that can be rotated around the longitudinal axis, characterized in that the impeller can be operatively connected to the drive unit in two fastening planes, whereby the impeller has a baseplate and blades arranged on the baseplate, and whereby the blades are located on the side of the baseplate facing the main air flow, whereby the baseplate is made up of an upper shell located on the side facing the main air flow and of a lower shell located on the side facing away from the main air flow, whereby the upper shell and the lower shell form a closed cavity with the cylindrical drive unit when in the installed state, whereby a first fastening plane is located on the upper shell and a second fastening plane is located on the lower shell.
 2. The radial or diagonal fan according to claim 1, characterized in that on the edge of the upper shell and of the lower shell facing the drive unit (200), there are fastening means in the appertaining fastening plane, and the drive unit has two flanges that are offset in the longitudinal axis, whereby the flanges have fastening means that can be detachably connected to the fastening means of the impeller.
 3. The radial or diagonal fan according to claim 2, characterized in that the upper shell and the lower shell are connected by screwed connections to flanges that are arranged on the cylindrical drive unit so as to be offset in the longitudinal axis.
 4. The radial or diagonal fan according to claim 3, characterized in that the fastening means in the upper shell, relative to the longitudinal axis of the rotatable cylindrical drive unit, are arranged radially offset to the fastening means of the lower shell.
 5. The radial or diagonal fan according to claim 4, characterized in that there are installation holes in the upper shell and/or in the lower shell opposite from the fastening means, which are concealed when in the installed state.
 6. The radial or diagonal fan according to claim 5, characterized in that the installation holes have a larger diameter than the holes in the lower shell and in the upper shell.
 7. The radial or diagonal fan according to claim 5, characterized in that the fastening means in the upper shell and the fastening means in the lower shell have holes or threaded bolts that are operatively connected to holes or threaded bolts of the flanges when in the installed state.
 8. The radial or diagonal fan according to claim 1, characterized in that the upper shell and/or the lower shell have centering means that cooperate with centering means on the flanges that have been put in place.
 9. The radial or diagonal fan according to claim 8, characterized in that the centering means are centering projections and centering indentations that cooperate during the installation of the impeller on the cylindrical drive unit.
 10. The radial or diagonal fan according to claim 1, characterized in that the upper shell is configured to be rotation-symmetrically curved in such a way that it curves in the direction of the main air flow.
 11. The radial or diagonal fan according to claim 1, characterized in that the upper shell has several sections that have at least one concave section or one convex section or one flat section.
 12. The radial or diagonal fan according to claim 1, characterized in that the lower shell is configured to be flat.
 13. The radial or diagonal fan according to claim 1, characterized in that the cavity has at least one reinforcement that runs as a round or polygonal ring axially around the cylindrical drive unit or extends radially relative to the longitudinal axis of the rotatable cylindrical drive unit.
 14. The radial or diagonal fan according to claim 1, characterized in that the blades arranged on the baseplate are configured with a shell design.
 15. The radial or diagonal fan according to claim 1, characterized in that the contours of the blades arranged on the baseplate are configured to be smooth on the side facing the main air flow.
 16. The radial or diagonal fan according to claim 2, characterized in that the flanges of the drive unit extend to differing extents radially relative to the longitudinal axis.
 17. The radial or diagonal fan according to claim 2, characterized in that installation holes are arranged in the flanges opposite from the fastening means, which are concealed when in the installed state.
 18. The radial or diagonal fan according to claim 17, characterized in that the installation holes have a larger diameter than the holes in the lower flange and in the upper flange.
 19. The radial or diagonal fan according to claim 1, characterized in that the drive unit is a rotor or a shaft connection.
 20. The radial or diagonal fan according to claim 1, characterized in that the impeller has a baseplate as a closure. 